| ROUND | IMPERIAL/METRIC |
| 1/4" | 2" |
| 3/8" | 2.1/8" |
| 10mm | 2.1/4" |
| 12mm | 60mm |
| 1/2" | 2.3/8" |
| 5/8" | 2.1/2" |
| 16mm | 65mm |
| 11/16" | 2.5/8" |
| 18mm | 2.3/4" |
| 3/4" | 3" |
| 20mm | 3.1/4" |
| 7/8" | 3.1/2" |
| 25mm | 3.3/4" |
| 1" | 4" |
| 1.1/8" | 4.1/4" |
| 30mm | 4.1/2" |
| 1.1/4" | 4.3/4" |
| 1.3/8" | 5" |
| 1.1/2" | 5.1/2" |
| 40mm | 5.1/2" |
| 1.5/8" | 6" |
| 1.3/4" | 6.1/2" |
| 45mm | 7" |
| 1.7/8" | 7.1/2" |
| 50mm | 8" |